I'm Feeling Refreshed

This is looking great, and we have a pretty nice app already. 0:00 However, there's one thing we've forgotten to take into account. 0:04 Right now we are getting weather data when the activity is created, or 0:07 when the app starts up. 0:11 That's all find and dandy. 0:12 But we can't really expect our users to close the app completely, and 0:14 start it up, every time they want to get the latest weather. 0:18 We can provide a better user experience than that. 0:21 Let's give them a way to update the weather. 0:25 If we take another look at our mock-up, and the resources provided 0:28 by the design team, we see there is this custom refresh button at the top. 0:31 Let's add this to our layout in a new image view, 0:36 which we'll design to allow users to tap on it. 0:39 This way we can make images a lot like buttons. 0:42 Full grab an ImageView. 0:53 Drag it over here to the top. 0:57 Choose the refresh resource. 1:02 We'll constrain it to the left, top, and right sides of our layout, 1:07 and the bottom will attach to the top of our location. 1:11 Let's zoom in a little bit, make it a little bit easier on ourselves. 1:16 Right? 1:22 Left, top, and this one will connect to our location. 1:24 For our purposes, we just need this image clickable. 1:32 And when a user clicks the image, we need the app to refresh the data and the view. 1:35 Let's turn our image into a very simple button. 1:40 Now what does our button do? 1:44 It gets a forecast, just like we're getting already in onCreate. 1:46 Let's do some refactoring of our code, and use a new method to get a forecast, 1:51 in a couple of different locations. 1:55 We want everything inside onCreate, 1:59 after super.onCreate down to the end of this if block. 2:01 So here, we can right click. 2:11 Refactor > Extract > Method. 2:15 Let's call it getForecast. 2:22 Nice, it would probably make sense too for 2:26 us to have this new method take a longitude, and latitude, as parameters. 2:29 Even though we're hard coding that information into our app right now, 2:34 we might want to extend this functionality in the future. 2:37 Let's come in here, getForecast, 2:41 double latitude, and double longitude. 2:46 Now we can cut these variables inside getForecast and 2:54 paste them up here above onCreate. 2:57 Paste them up here. 3:03 And we'll make them final. 3:05 And change our call to get forecast now to use those. 3:11 Now we need a new method for a button. 3:18 Let's make a new method down at the end of our file. 3:21 We'll do public void, call it refresh, OnClick. 3:30 We'll take a view. 3:39 And we'll want to call our getForecast method with our new default arguments. 3:43 And accept our imports for our view. 3:56 Okay, now where can we use this? 3:59 We're naming this as an OnClick, but 4:02 it doesn't really seem like there's enough code to do that, right? 4:05 Well, there's a simple way to add button like functionality to an image, 4:08 such as our refreshImageView. 4:13 If we head into the activitymain.xml file again, 4:15 go to text, Find our ImageView. 4:21 In this ImageView, we can call a function when the image is clicked. 4:27 Add the following line after the last android:layout setting. 4:32 We want android:onClick, and the name and 4:38 the method that we just wrote, which was refresh on click. 4:41 So what's happening here? 4:47 Well, now when a user clicks our imagine, the object receives an OnClick event. 4:49 The value for this attribute is the name of the method that we want to call, 4:55 when the click event is triggered. 4:59 The activity that is responsible for the associated layout in our main activity in 5:01 this case, then implements the method that is called from a click event. 5:06 As I mentioned, 5:11 this is a simple way to make images act like buttons with click events. 5:12 There are some things to think about with this bill. 5:16 First, the method that is called in the android onClick method, 5:19 must have the same signature that we use for refresh on click. 5:23 It must be public, and avoid return type, and define a view as it's only parameter. 5:27 This method also doesn't work in all situations. 5:32 For instance, if you need to declare the click behavior in a fragment subclass, or 5:36 you instantiate the button at run time. 5:41 In those situations, you'll need to define an onClick listener programatically, 5:44 rather than in an XML layout. 5:49 For our purposes though, this works. 5:52 Let's run this and try it out. 5:55 Well, it seems to be working. 6:08 We're seeing new data show up in the log, 6:10 however, the user won't know unless something changes with the data. 6:13 When we get data from the network and the background like this, we usually want to 6:18 display something to the user to indicate that work is being done. 6:22 There are cases where we don't want to display anything, but 6:26 in this case, it's better to add some sort of indicator. 6:29 Let's just add a simple toast message to our refresh onClick method, 6:33 to let the user know that data is being refreshed 6:37 Toast.makeText. 6:47 We'll just say refreshing data. 6:53 We'll do it length long. 7:00 And then we'll call show. 7:01 Let's run that again. 7:05 And there's our toast. 7:14 Great, the user will see that data is being refreshed, 7:16 even if the data doesn't change on the screen. 7:20